A known means for evaluating the efficiency of a feed for fattening ruminants is the so-called "feed efficiency". The feed efficiency is the ratio of the quantity of ingested feedstuff to the gain in live weight of the animal being fattened. A decrease in the quantity of feed per unit of gain in live weight of the animal represents an improvement of the feed efficiency. In order to minimize the amount of feedstuff required to fatten an animal, livestock feeders obviously try to increase the feed efficiency of the feedstuff Further, for economic reasons, livestock feeders try to reduce as much as possible the amount of ingested feedstuff per unit of gain in live weight. Livestock feeders are particularly concerned with increasing the feed efficiency of feedstuffs in connection with the fattening of ruminants for the production of meat, since only part of the ingested feedstuff is used by the ruminants for growing.
In this connection, it has previously been proposed to protect at least certain constituents of the feedstuff in order to avoid degradation inside the rumen and in order to permit these constituents of the feedstuff to reach the duodenum of the animal. For example, it has been proposed to protect certain constituents of the feedstuff by tanning or by encapsulation.
In addition, in order to improve the feed efficiency, it has been proposed to use ionophore antibiotics, especially monensin, or lasalocid. These ionophore antibiotics act at the level of the rumen by modification of the fermentations therein. The consequence of these ionophore antibiotics is increased production of propionic acid, which propionic acid is the principle source of endogenous glucose, and decreased production of acetic and butyric acid. However, although ionophore antibiotics provide a degree of improved feed efficiency, it is desirable to further increase feed efficiency since the profit margin in feeding ruminants is usually very narrow.
It has also been proposed to introduce probiotic microorganisms or isoacids into the feedstuff. However, the results of the use of probiotic germs or isoacids have not provided a sufficient systematically beneficial effect.
Finally, a method of optimizing the assimilation of the feed ration in fattening ruminants is described in UK Patent Application GB 2,159,690. This patent application proposes providing ruminants with an effective amount of sorbitol in addition to their normal feed ration, and suggests that the gain in weight is increased without a correspondingly larger consumption of feedstuff.
The present Applicants have now discovered that the feed efficiency is surprisingly and substantially increased when ruminants to be fattened ingest an effective amount of both sorbitol and at least one ionophore antibiotic in addition to their normal feedstuff.
Therefore, it is an object of the present invention to provide a method of feeding ruminants which achieves a higher feed efficiency than prior feeding methods.
It is a further object of the present invention to provide a feed supplement which effectively increases the feed efficiency of feeding ruminants.
It is another object of the present invention to provide a feedstuff for ruminants which includes a feed supplement for improving the feed efficiency of feeding ruminants.
Additional objects and advantages of the present invention will be apparent from the following detailed description of the invention and the examples thereof which follow.